A study on the relation bewtween an Arabidopsis P4H9 T-DNA insrtional mutant and ethylene production and perception
2010
Mroued, S.
The prolyl-4-hydroxylase (P4H) gene family in Arabidopsis consists of thirteen genes; however only two, P4H1 and P4H2, were characterized thoroughly. In this study, we further explored the biological role of AtP4H9 in plants, using a T-DNA knockout mutant, Atp4h9-1. Atp4h9-1etiolated seedlings showed a phenotype with longer hypocotyls and roots when compared to wild type. Quantification of ethylene production revealed lower levels of ethylene in p4h9-1 etiolated seedlings by approximately 38% which justifies the observed phenotype and suggests that p4h9-1 mutant might be affecting ethylene production. To further explore this assumption, the p4h9-1response to ACC (ethylene precursor) was characterized. According to preliminary results, Thep4h9-1 mutant might be able to restore wt phenotype when supplemented with approximately0.25 um ACC. Moreover, both wt and p4h9-1 etiolated seedlings displayed a phenotype with similar average root and hypocotyl length when supplemented with 1um ACC, while their ethylene production rates were different. p4h9-1 seedlings produced less ethylene indicating involvement in its production but not in perception and signaling. Consistent to these data, ACC oxidases and some ACC synthases show significant decrease in expression in p4h9-1 etiolated seedlings, partially justifying the observed decrease in ethylene production. In addition,transformed Arabidopsis plants expressing the P4H9 promoter-GFP construct are currently under investigation.
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